The proposed research is founded on the observation by one of us that natural populations of drosophila mojavensis extend their longevity in alcohol atmospheres. The length of life extension is correlated with the frequency of alleles at the ADH locus. We will begin the present study by surveying wide spread natural populations of D. mojavensis for allelic content at the following loci; ADH, ODH and AO. A coordinated assay of longevity under alcoholic atmospheres will be conducted on each population. The results of this work will be related to the natural environment. Furthermore the survey will provide us with a number of strains with diverse genetic backgrounds. We will choose approximately ten strains, all of which will be utilized in an artificial selection scheme designed to produce lines that demonstrate both high and low longevity. Each high and low line will be investigated throughout the selection regime for allozymic content and specific activity of the ADH, and AO genetic loci. After ten generations of selection particular high and low lines will be compared for changes in: 1) Allozymes present, 2) Activity profiles, 3) Enzyme kinetics and 4) Amount of enzyme produced. Those lines which show specific differences at alcohol metabolizing loci will be corssed to determine the genetic mode associated with the longevity response. This work should provide insight into how natural selection operates to produce a specific life span in a particular environment as well as formulation of working hypotheses on the mechanisms of aging.